Spi 29-285-4 Class Zz Plus Plug Gage 0.285 in Steel

Product Description

The SPI 29-285-4 is a Class ZZ Plus plug gage designed for precision go/no-go inspection of bored holes and machined openings. It measures a nominal diameter of 0.285 inches with a tolerance of 0.0002 inches, making it suitable for quality control in close-tolerance manufacturing environments. Constructed from steel, this gage provides the durability and dimensional stability required for repeatable shop-floor inspection work. Machinists, toolmakers, and quality technicians use plug gages like this to verify that drilled, reamed, or bored holes fall within specified dimensional limits before parts advance through production.

Class ZZ Plus plug gages are typically applied in production inspection settings where high-volume checking of through-holes or blind holes is required. The 0.285-inch diameter range fits a range of common machined feature sizes found in light manufacturing, precision fabrication, and assembly operations. This gage is suited for bench inspection, incoming parts verification, and in-process quality checks on machined components.

Key Features

• Nominal measurement diameter of 0.285 inches for precise hole inspection
• Class ZZ Plus tolerance of 0.0002 inches for close-tolerance go/no-go verification
• Steel construction for dimensional stability and shop-floor durability
• Compact and lightweight at 0.2 pounds for easy handheld use
• Single-piece packaging suitable for individual replacement or toolroom stocking

Compatibility

Designed as a standard Class ZZ Plus plug gage for inspecting machined holes with a nominal diameter of 0.285 inches in general precision manufacturing and quality control applications.

Installation Notes

Plug gages are used by machinists and quality inspection personnel and require no permanent installation. Before use, clean the gage and the hole being measured to remove chips, coolant, and debris that could affect reading accuracy. Do not force the gage into an undersized opening, as this can damage the gage surface and compromise calibration. Gages should be stored properly and recalibrated periodically per your facility quality system requirements.